Diphenhydramine is an antihistamine that helps to relieve allergic symptoms for individuals facing watery eyes, runny nose, skin rashes or similar symptoms. In some cases, Diphenhydramine is also used as a sleep aid. This medication is available as an over the counter drug as well as in injection form that requires a prescription. A generic form of medication is also available.
Diphenhydramine is an antihistamine that reduces the effects of histamine, a natural chemical produced by the body. Diphenhydramine is used to manage symptoms of the common cold, hay fever, and allergy. Such symptoms include itching, rash, itchy eyes, nose or throat and watery eyes.
Diphenhydramine can also be used to treat dizziness, vomiting and nausea caused by motion sickness, to induce sleep, and to treat certain symptoms of Parkinson's disease.
Diphenhydramine works by blocking histamine, a natural substance made by the body during an allergic reaction. Diphenhydramine also blocks acetylcholine, another natural substance. This block causes a drying effect on symptoms like a runny nose and watery eyes.